Characterization and analysis of InGaN photovoltaic devices

The InGaN material system is investigated to achieve high efficiency solar cells, using tandem and quantum-well structures to implement high efficiency concepts. Here InGaN p-i-n and quantum-well solar cells are designed, grown by MOCVD and fabricated into mesa devices. They are electrically characterized by I-V response under dark, white light and UV illumination and internal quantum efficiency (IQE). Material characterization is done by X-ray diffraction, photoluminescence and photoemission. InGaN solar cells with high In compositions are grown in two configurations, one incorporating it into the i-region of a p-i-n solar cells, and the other incorporating as the well-region of a quantum-well device. A QE of 8% was measured from these quantum-wells. Solar cells with In lean In_0.07Ga_0.93N p-i-n device structures show an IQE of 19% as well as photoemission at 500 nm, confirming the suitability of the material for photovoltaic applications.